This kind of loop-shaped handle is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. SHO-63-44310. This handle has a vertical position adjusting structure so that the handle is vertically adjustable to a height. This handle structure will be described with reference to FIGS. 14 and 15 hereof.
Referring to FIGS. 14 and 15, the handle 100 is loop-shaped handle and has a pair of left and right handle bars 102, 102 obliquely extending rearwardly upwardly from a handle mounting portion 120 provided at the rear of a tiller body (not shown), and a linear horizontal handle bar 103 extending transversely of the body for connecting the rear ends of the handle bars 102, 102.
A C-shaped member 104 protruding toward the tiller body is mounted to a central portion of the horizontal handle bar 103. A vertical position adjusting grip lever 105 for controlling the relative height of the bar to the tiller body is attached to the C-shaped member 104.
To the proximal end of the handle 100, as shown in FIG. 15, an arc member 106 with a plurality of pin holes 107 formed above and below is mounted. A lock pin 108 to be fitted into or removed from one of the pin holes 107 is connected to a release wire 109 which in turn is connected to the vertical position adjusting grip lever 105.
To the rear of the left and right handle bars 102, 102, clutch grip levers 130, 130 for on/off control of clutches (not shown) are attached via release wires 131, 131 connected to the clutches.
The above handle 100 structure requires adjustment of height of the handle 100 so as to correspond to different work postures taken for tilling, mere traveling and other operations with the tiller. The height adjustment is made by holding the grip lever 105, pulling the release wire 109, releasing the engagement between the lock pin 108 and one of the pin holes 107, and then aligning the lock pin 108 with one of the pin holes 107 corresponding to the height to which the handle 100 is to be adjusted, releasing the grip lever 105, engaging the lock pin 108 with the pin hole 107, and thereby adjusting the handle 100 to a desired height.
The above handle structure allows comfortable work postures for which, however, it requires the operation of engaging and disengaging the lock pin 108, taking time in height adjustment. The above vertical position adjustment configuration consists of a number of components and is thus complicated, making it difficult to reduce production costs. For operating the clutches with the above clutch grip levers 130, 130 when performing tilling operation holding the horizontal handle bar 103, it is required to change the positions of the hands to the left and right handle bars 102, 102. This results in the problem that the effect of forming the handle 100 in a loop cannot be exerted.
Another example tiller with a pair of left and right bar handles extending obliquely from the rear of a tiller body rearwardly upwardly and arranged to be vertically adjustable at their proximal ends is disclosed in Japanese Utility Model Laid-Open Publication No. HEI-2-134801. This tiller is shown in FIG. 16 hereof.
Referring to FIG. 16, the tiller 200 has a handle supporting member 211 provided on an upper central portion of a tiller body 210 and extending rearward. A pair of left and right bar handles 220 is vertically swingably attached to a rear end portion of the handle supporting member 211 via a shaft 212. The bar handles 220 can be adjusted in height by unfastening a handle height adjustment lever 213, then vertically swinging the bar handles 220, and fastening the lever 213 at a desired height, so that the handle height can be changed according to working conditions.
While the above tiller 200 provided with the handle height adjustment lever 213 can improve the work posture of an operator, it has the problem of an increased number of components and increased production costs.
As another example of a clutch lever configuration for controlling a tiller in which clutch levers are formed in loops like an operating handle is disclosed, for example, in Japanese Patent Laid-Open Publication No. HEI-5-8653. This clutch lever configuration is shown in FIG. 17.
Referring to FIG. 17, a looped driving clutch lever 302 and working clutch lever 303 are swingably supported on a rear lower portion of a looped operating handle 300 via a bracket 301. The two clutch levers 302, 303 are provided in proximity but are so far from a handle grip 300a that it is required to unhand the handle grip 300a to switch the clutch levers 302, 303 from off to on, resulting in the problem of reduced clutch operability.
In this context, there is a demand for a walk-behind tiller which allows for comfortable work postures in different operations and improves maneuverability of a clutch lever.